The negatively-charged nitrogen-vacancy (NV) color center in diamond possesses many useful properties, including without limitation: long electronic spin coherence times at room temperature; optical mechanisms for initializing and detecting their spin states; and electron spin resonance (ESR) techniques that allow for coherent spin manipulation. The NV color center has generated much interest for scalable applications in quantum information and metrology, such as sensitive detection of electric and magnetic fields.
Dynamical decoupling techniques have been used to reduce the effective interaction of single NV spins with other spin impurities in the environment, enabling significant improvements in the NV single-spin coherence lifetime.
For multi-spin systems, for example ensembles of NV color centers in diamond containing large densities of NV spins, realizing long spin coherence lifetimes remains a challenge. Likewise, there is a need for increasing the sensitivity of magnetometry and other multi-spin metrology that involves ensembles of NVs or other spin impurities.